Processes for scouring textiles

ABSTRACT

Textile fibers which have been desized and are about to be bleached are scoured with an alkaline caustic solution containing a surfactant and a synergistic inhibiting agent such as a mixture of amino tri(methylene phosphonic acid) and triethanolamine. This process provides fibers with a substantially reduced impurity level and an end product which is substantially more conducive to subsequent bleaching and dyeing processes.

Ffi KR 565s7 0 United States Patent 1151 3,645,670

Kowalski Feb. 29 197 2 [54] PROCESSES FOR SCOURING TEXTILES 3,234,140 2/1966 lrani ..252/l86 [72] lnvemor: Xavier Kowalski, Creve Coeur, Ma 3,476,505 1 1/1969 Klmer et al ..8/ I39 [73] Assignee: Monsanto Company, St. Louis, Mo. Examine -Mayer W in latt Attorney-Herbert B. Roberts, Roger R. Jones, James J. Mul- [22] led: 19,70 len and Neal E. Willis 21- A 1. No.2 16 244 1 PP 57 ABSTRACT 52 11.5. c1 ..8/l39, 8/107 8/108, Textile fibers which have been desiled are m be 252/99 232/186 bleached are scoured with an alkaline caustic solution con- [5 l Int. Cl ..l )01c 1/00 taming Surfactant and a Synergistic inhibiting agent Such as a [58] Field 01 Search 8/l39 107 1 08- 252 99 186 mixture ami'w tri(mthyl'me acid) and I l triethanolamine. This process provides fibers with a substan- [56] References Cited tially reduced impurity level and an end product which is substantially more conducive to subsequent bleaching and dyeing UNITED STATES PATENTS Processes- 3,234,l24 2/1966 Irani ..8/l39 4 Claims, N0 Drawings PROCESSES FOR SCOURING TEXTILES The present invention relates to an improved process for bleaching and dyeing textile materials. Specifically, this invention is concerned with scouring materials with a composition containing a novel synergistic mixture which functions as an inhibiting agent for the prevention of the precipitation of iron (hydroxides) and alkaline earth metal salts such as calcium carbonate.

Preparing textile materials for bleaching, dyeing and finish- Publishers, lnc., New York, New York 1955, edited by Kyle Ward, Jr., and which is incorporated herein by reference. A discussion per se of the scouring step starts on Page 144 of said publication. I

In general, scouring is the third major step in the abovedescribed textile-finishing process. The purpose of the scouring step is to remove foreign matter left on the textile material after desizing.

The scouring process is desirable in order to attempt to remove impurities or foreign matterand thus ultimately prepare a whiteness in color" product suitable for subsequent bleaching and dyeing and effecting a uniformity of color thereon. Generally, commercial scouring (including boiling) processes involve contacting the textile material with alkaline aqueous solution (bath) containing a caustic material such as sodium hydroxide and a synthetic organic surfactant.

In conjunction with the use of these scouring baths, one of the impurities is iron, either in the ferric or ferrous state, but generally the former.

1n the past, it has been suggested in U.S. Pat. No. 3,234,124, which is incorporated herein by reference, that certain amino tri(lower alkylidene phosphonic acids) and their water-soluble salts are effective in sequestering'iron in the scouring of wool cloth. However, it has been found in the instant invention that when the scouring bath not only contains at least 1 ppm. iron but also contains at least 10 ppm. of an alkaline earth metal cation such as calcium, for example present as CaCO the iron is not effectively sequestered but precipitates, adheresto the textile fiber'and subsequently causes a serious discoloration problem, i.e., the fibers will exhibit a distinctive discoloration.

Thus the suggested use by U.S. Pat. No. 3,234,124 of said phosphonic acids or salts per se in the scouring process was found not to be substantially completely effective in that the subsequently bleached textile material did not exhibit a better than fair whiteness in color. By the practice of the present invention, however, the whiteness of the bleached material is substantially improved. v

Accordingly, it is an object of this invention to improve the process of the typedescribed so as to enhance the appearance of the textile material treated and to keep iron (for example, in the form as Fe(OH) and alkaline earth metals (in salt form) from adhering to the surface of said material and thus to promote a more effective bleaching and dyeing step.

Other objects will become apparent in view of the subsequent detailed description and appended claims.

It has been unexpectedly found that the above objects can be accomplished by including a synergistic inhibiting agent which is a mixture of an amino tri(lower alkylidene phosphonate) and an amino alcohol (hereinafter defined) in the aqueous alkaline scouring bath in addition to the caustic material and surfactant. The amino tri(lower alkylidene phosphonates) have the general formula:

tris-isopropylamine;

wherein X and Y represent hydrogen or a lower alkyl containing, for example, from one to four carbon atoms and R is from the group hydrogen and cations which are capable of forming water-soluble salts. Compounds illustrative of the acids (where R is hydrogen) are amino tri(methylene phosphonic acid) (herein referred to as ATMP). amino tri(ethylidene phosphonic acid), and amino tri(isopropylidene phosphonic acid).

it is to be understood in addition to the acids per se, the water-soluble salts (where R is a metal cation such as sodium) are also included within the scope of the present invention. The preferred salts are the sodium salts, particularly the pentasodium salt. Other alkali metal salts, such as potassium, lithium andthe like, as well as mixtures of the alkali metal salts may be used. In addition, any water-soluble salt, such as the ammonium salt, e.g.,

N[Cl-l PO (NH (CH PO HNH and the amine salts,

which exhibit the characteristics of the alkali metal salt may be also used topractice the invention.

The amino alcohols which have been found to exhibit synergism (when used with the above-described phosphonic acids or salts) in this invention include mono-, diand triethanolamine (herein referred to as TEA); mono-, diand monoand diisobutanolamine; butanolamine; dibutyl amino ethyl alcohol; dibutyl amino propyl alcohol; dibutyl amino isopropyl alcohol; bis( 2-hydroxyethyl) butyl amine; butyl ethyl 2,2 dihydroxy amine; dibutyl ethyl 2,2',2"trihydroxy amine; bis(2-hydroxyethyl) methyl amine and dipropyl ethyl 2,2',2 trihydroxy amine.

It is found desirable to use at least about 0.01 percent by weight of said'synergistic inhibiting agent based on .the total weight of the aqueous solution which contains the caustic, surfactant, said inhibiting agent, and water. It is to beunderstood that the amount of inhibiting agent necessary depends upon the level of iron and (e.g.) calcium contamination of the scouring bath. However, the general usage of the above-mentioned inhibiting agent indicates a practical upper limit is about 2.0 percent by weight. The preferred range is from about 0.1 percent to about 0.5 percent.

The inhibiting agent is a mixture of the above-mentioned phosphonates and the amino alcohol. The weight ratio of said phosphonate to said amino alcohol is from about 0.5:] to about 4:1, preferably from about 0.75:1 to about 1.5: 1.

It is to be understood that the term textile materialas used herein includes any natural and/or synthetic fibrous base material such as cotton, nylon, viscose rayon, Dacron, polyester, hemp, linen, jute, and blends thereof such as, for example, cotton-Dacron, cotton-Dacron-viscose rayon, cottonnylon-viscose rayon, cotton-Dacron-nylon, cotton-nylon, and cotton-polyester (all in various weight ratios).

.The specific synthetic organic surfactant can be any of a wide variety of surface active agents. Typical surfactants are described in U.S. Pat. No. 2,846,398 and U.S. Pat. No. 3,159,581, both of which are incorporated herein by 'reference. Furthermore, other publications which describe surfactants which can be used in the present invention processes include Schwartz and Perry, Surface Active Agents," lnterscience Publishers, New York (1949) and The Journal of American Oil Chemists Society, Vol. 34, No. 4, pages -216 (Apr., 1957), both of which publications are incorporated herein by reference. The amount of surfactant will vary, depending upon various process conditions and any amount can be used as long as no substantial adverse effect is incurred in the scouring operation.

The most common material presently used in the scouring bath to render it an alkaline solution with a pH above 7 (generally in the range of pH 10 to pH 14) is sodium hydroxide. It is to be understood that any caustic material can be used in order to effect a pl-iabove 7. The amounts of caustic material, e.g'., NaOH, used in the scouring bath will vary depending upon the temperature, desired pH, (sometimes) textile material to be treated, and the like. in general, the amounts of caustic used are from about 1 percent to about 4 percent by weight based on the total weight of the alkaline aqueous solution.

The temperature of the bath is desirable in the range of from about 7 2F. to the boiling point of the scouring solution but temperatures'from about [40 F. to' about 210 F. are preferred. it is to be understood that higher temperatures, such as 250 F. to 300 F., can be used (with the aid of superatmospheric pressure) where one so desires.

The practice of the invention and the advantages provided thereby are further illustrated by the following examples which are not intended to be limitative:

EXAMPLEI As a practical demonstration of the formation and prevention of formation of undesirable precipitates of iron and calcium in scouring baths, 1 liter of boiling caustic solution con taining 80.0 grams of a SO-Weight/percent sodium hydroxide solution and 12.0 grams of Biofax P-35, a phosphated surfactant typical of those used in the industry, were used in this experiment as the scouring bath. The water was of sufficient hardness to provide approximately lo p.p.m. Fe*** and 50 p.p.m. CaCO Seven 20-gram fabric samples of 35 percent cotton and 65 percent polyester were tested. Each fabricsampic was scoured in the bath described above. In scouring bath designated Solution 1 in Table I, no inhibiting agent was used. In Solution 2, only 2.3 grams of ATMP was used; in Solution 3, only 2.3 grams of triethanolamine (TEA) was used. in Solutions 4, 5. 6 and 7, 2.3 grams of the indicated inhibiting agent was used. Each sample was scoured for l hour at 210 F. and rinsed twice with water at 210 F. for 30 minutes each time. The seven scouring solutions were then allowed to stand at 72 F. The results are shown in the following Table 1.

EXAMPLE-iv Six 20-gram samples of a bleached white cotton fabric were subjected to the same scouring procedure as that described in the above Example I. Each fabric sample was individually scoured with only one scouring solution which are shown in Table I] under Sample Nos. 1 through 6. A seventh sample of bleached cotton was used as a control or standard.

The purpose of this Example IV was to ascertain to a higher degree the staining, if any, of bleached cotton fabric by iron (from iron precipitates) which might not be as easily detectable on unbleached cotton fabric. The degree of staining is set forth in terms of "fabric whiteness" as determined by a Gardner Automatic Color Difference Meter made by Gardner Laboratory, lnc., Bethesda, Maryland. Thefabric whiteness" numbers shown in Table ll were determined relative to a standard (MgO filter being equal to 100) which was as close to perfect whiteness as is possible. The results of this Example IV are set forth in Table II.

. g, 4 Fabric whiteness number 5 Decrease in fabric whiteness number Original fabric.

l Treated at 210 F. for 1 hour, followed by two rinses at 210 F., 10 minutes each rinse.

$401751 solution of ATMP and TEA; ATMP:TEA (active basis) wt. ta 0 z 2140?? 6soilutlori of ATMP and TEA; ATMP:'IEA (active basis) wt. ra 0 l flssloiution of ATMP and TEA; ATMPzTEA (active basis) wt.

rat

5 The higher the number, the whiter the fabric; difierence of 2 in whiteatsnseeaiszes li smas es and 65 72 so o it as TABLE I Sequestration of iron in strong caustic soda scotgirggolutions: 4.0% NaOH, l0 p.p.m. Fe+++, p.p.m.

Solution number 1 2 3 4 5 6 7 A.\IPT, percent 0 0.2 0 0.1 0.125 0.15 0.115 'Iriethanolamine (TEA), percent 0. 1 0. 075 0.05 0.025

Initial appearance of solution at 72 F Preeipitate formed, hours 1 0 0 0,2 Light brown solution..- {Light brown solution..- lluilkyn Solution appearance after 2 months at 72 F... liniw'iijiiiry 5 3E111: Browii; ii 6593; 5 1511: :1 H1259}; wiiii'fififi i 1 Solutions were allowed to stand at 72 F.

Example I above is repeated again with the sole exception that butanolamine is substituted for triethanolamine (TEA). Substantially the same results as those disclosed in Table I are obtained. 7 EXAMPLE lll Example I above is individually repeated two times with the 70 sole exception that the specific water used contained respectively 3 p.p.m. Fe and 20 p.p.m. Fe instead of the water. used in Example I which contained 10 p.p.m. Fe Substantially the same results as those disclosed in Table l are obtained.

In conjunction with Table ll, it is vividly demonstrated that the unique inhibiting agents of the present invention exhibit a synergistic effect and are substantially better than either the phosphonate per se or the amino alcohol per se. Specifically, it can be seen that with no inhibiting agent (or sequestrant) in the scouring bath, the fabric had a whiteness number of 65; with only ATMP the value was 72 and with only TEA, the value was 80. But with a combination of ATMP and TEA, i.e., the novel inhibiting agents of the present invention, the average value was 89, a significant difference. The superiority of these novel inhibiting agents is thus seen.

The foregoing examples have been described in this specification for the purpose of illustration and not limitation. Many other modifications and ramifications will naturally suggest themselves to those skilled in the art based on this disclosure. These are intended to be comprehended as within the scope of this invention.

What is claimed is:

l. in a process for treating textile materials which comprises the steps of singeing, desizing, scouring with an alkaline aqueous solution containing a caustic material and a surfactant,

bleaching, souring, mercerizing, dyeing or printing, and finishing, the improvement'which consists essentially of incorporating into the scouring solution at least 0.01 percent by weight, based on the total weight of the scouring solution, of an inhibiting agent consisting of an amino tri(lwer alkylidene phosphonate) having the formula tyl amino propyl alcohol; dibutyl amino isopropyl alcohol; bis(2hydroxyethyl) butyl amine; butyl cthyl 2,2 dihydroxy amine; dibutyl ethyl 2,2',2 trihydroxy amine; bis(2-hydroxyethyl) methyl amine; dipropyl ethyl 2,2,2" trihydroxy amine; and mixtures thereof; the weight ratio of said phosphonate to said alcohol being from about 0.5:l to about 4:1.

2. The process as set forth in claim. 1 wherein the concentration of the inhibiting agent is from about (H to about 0.5 percent by weight.

' 3. The process as set forth in. claim 2 wherein the temperature of the scouring solution during the textile treatment is from about l40 F. to about 2 10 F.

4. The process as set forth in claim 3 wherein the inhibiting agent is a mixture of amino tri(methylene phosphonic acid) and triethanolamine and the weight ratio respectively is from about 0.75:1 to about 1.5:]. 

2. The process as set forth in claim 1 wherein the concentration of the inhibiting agent is from about 0.1 to about 0.5 percent by weight.
 3. The process as set forth in claim 2 wherein the temperature of the scouring solution during the textile treatment is from about 140* F. to about 210* F.
 4. The process as set forth in claim 3 wherein the inhibiting agent is a mixture of amino tri(methylene phosphonic acid) and triethanolamine and the weight ratio respectively is from about 0.75:1 to about 1.5:1. 